DRAWMER 1969 OPERATORS
QUICK SET UP
CAUTION - MAINS FUSE
TO REDUCE THE RISK OF FIRE REPLACE THE MAINS FUSE ONLY WITH A FUSE
THAT CONFORMS TO BS EN 60127-2:1991 SHEET III. 250 VOLT WORKING, TIME
DELAY TYPE AND BODY SIZE OF 20mm x 5mm.
THE MAINS INPUT FUSE MUST BE RATED AT 250mA WHERE THE MAINS INPUT VOLTAGE
SWITCH IS SET TO 230 VOLTS AC. AND 500mA WHERE THE MAINS INPUT VOLTAGE IS
115 VOLTS AC.
THE REAR PANEL H.T. FUSE MUST ALWAYS BE RATED AT 50mA, IRRESPECTIVE OF THE
MAINS VOLTAGE SETTING.
CAUTION - MAINS CABLE
DO NOT ATTEMPT TO CHANGE OR TAMPER WITH THE SUPPLIED MAINS CABLE.
CAUTION - SERVICING
DO NOT PERFORM ANY SERVICING. REFER ALL SERVICING TO QUALIFIED
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE.
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The 1969 is a hybrid vacuum tube/semi-conductor, dual-channel compressor
which has numerous applications in studio recording, live sound, location
recording, post-production and as part of a musician's rack system. A
major advantage of the hybrid approach is that it combines the reliability
and stability of modern solid-state designs with the warm, detailed sound
of vintage classic tube designs. In addition, the 1969 incorporates two
low-noise microphone preamplifiers with provision for phantom powering,
plus a versatile instrument preamplifier with passive EQ and brightness
switch. The instrument preamplifier may be routed through either
compressor channel (or both) and is suitable for a variety of signal
sources, from electric guitars and basses to electronic keyboards. It
incorporates the same type of passive equalisation circuitry used in
traditional tube guitar amps, while the Bright switch emulates the voicing
of a typical guitar amplifier. This stage may be deliberately overdriven
if required to add tonal coloration to an instrument, and with the
addition of an external speaker simulator, overdriven guitar sounds may be
Directly Injected ("DI'd") into the mixing console.
There are two valve stages in each audio signal path and the compressor
section is designed to provide a soft-knee characteristic which
contributes both to the sweet sound of the unit and to its ease of use.
Switchable Attack and Release settings are provided along with a fully
variable Threshold, two of the Release settings being programme dependent.
Traditional moving coil meters are used to monitor either the gain
reduction or the output signal level while an output Gain control provides
up to 20dB of make-up gain. The microphone input stages feature extremely
low noise, balanced input circuitry with additional tube amplification,
enabling modern microphones to take on the characteristics of older tube
models. Phantom power is individually switchable on the two channels and a
peak overload LED warns when clipping is imminent. Two sets of insert
points on the rear panel allow additional effects to be added either
before or during compression.
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Further to its more conventional applications as a general
studio compressor, the 1969 is also particularly effective when used to
treat complete stereo mixes. The subtle tube colorations add warmth and
depth to the sound, while at the same time emphasising mid-range and
high-frequency detail. For high quality location recording, the 1969 makes
the perfect partner for a DAT machine, as it combines the functions of
stereo mic preamp with that of a compressor. The mic inputs provide up to
60dB of gain while maintaining a noise figure comparable with the better
'in-desk' mic preamps. Soft-knee compressors are generally preferable for
unobtrusive level control and the system used in the 1969 provides firm
control without the side-effects of a fixed, hard-knee design. As an
instrument amplifier, the 1969 provides gain, EQ and compression making it
ideal for DI'ing guitars, basses and even keyboards. The tube gain stages
are versatile enough to provide a clean, punchy sound or the gain may be
increased to provide the type of overdrive sound associated with tube
guitar amplifiers. Furthermore, when the compressor is deliberately
overdriven, it can be used creatively to produce level 'pumping' effects
which can be useful both on electric guitar or rock vocal sounds. The Aux
input may also be used for processing the output from a dedicated guitar
preamplifier, where the EQ can be used to further tailor the sound before
it is compressed. By adding compression to an overdriven sound, the degree
of sustain can be maintained at a lower overdrive setting while the tube
circuitry will add warmth and punch.
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The 1969 is designed for standard 19" rack mounting and occupies 2U
of rack space. Avoid mounting the unit directly above power amplifiers or
power supplies that radiate significant amounts of heat and always connect
the mains earth to the unit. Fibre or plastic washers may be used to
prevent the front panel becoming marked by the mounting bolts. Because the
tube circuitry generates more heat than an equivalent solid-state design,
it is advisable to leave space above the unit to allow the heat to
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The inputs and outputs are electronically balanced on
conventionally wired XLRs (pin 1 screen, pin 2 hot, pin 3 cold and XLR
shell is connected to chassis). The 1969 fully conforms to the EMC
standards, if you propose to use the unit where it maybe exposed to high
levels of disturbance such as found close to a TV or radio transmitter we
suggest that the screen of the signal cable is connected to the chassis
connection on the XLR type connector. The operating level is nominally
+4dBu. If earth loop problems are encountered, do not disconnect the mains
earth but instead, try disconnecting the signal screen on one end of the
cables connecting the outputs of the 1969 to the patchbay. Balanced
operation is recommended. The side-chain access point and the two
different level insert points are unbalanced. The intended use of the
audio insert jacks would be to patch in EQ (eg 1961), reverb or similar
processing. Connection is via stereo 1/4" jacks, the wiring
convention being: ring is signal send, tip is signal return and sleeve
The unit will have been supplied with a power cable suitable
for domestic power outlets in your country. For your own safety it is
important that you use this cable. The unit should always be connected to
the mains supply earth using this cable.
If for some reason the unit is to be used at a mains input operating
voltage which is different to that as supplied, the following procedure
must be carried out.
- Disconnect the unit from the mains.
- Using a number 1 size pozidrive
screwdriver, remove the two self-tapping screws holding the voltage
selection switch cover plate on the rear panel.
- Remove the cover plate and slide the
switch fully to its opposite end.
- Rotate the cover plate one half turn,
(180) and refit the two screws.
- Fit a correctly rated fuse for the
selected operation voltage.
- Re-connect to mains power source.
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With the exception of the Aux preamp section, both channels of the 1969
are identical and may be used independently or linked for stereo
operation. In both the linked modes, only Channel 1 compressor controls
are functional and serve as the stereo master. In Stereo Link mode, both
channels track together to avoid the inevitable image shifting that would
occur if the two channels of a stereo signal were treated independently.
Source Select: This rotary switch
selects the compressor input source. The Line and Mic inputs are via the
rear-panel XLRs while the Aux input is available on the front panel. The
two Mic positions offer a choice of Mic input with or without +48V phantom
powering; a red LED indicates that phantom power is active.
Note: if the Aux input is to be used at the same time as a Mic input, it
is recommended that the Mic input be processed through the upper channel
and the Aux input through the lower channel as this minimises crosstalk
between tube amplification stages sharing the same envelope.
Phase Reverse: This will invert the
phase of the selected input signal. Use of the Phase Rev feature is
usually required in multi- mic situations where phase anomalies or arrival
time discrepancies need to be compensated for. It is advisable to check
for mono compatibility when using phase reversal within a multi-mic
High-pass: The signal path
incorporates a switchable high-pass filter which may be set to 50Hz, 100Hz
or Off. Its use is to attenuate low frequency signals that might otherwise
prove troublesome, eg. traffic rumble or stage vibration.
Threshold: Determines the input level
above which gain reduction will be applied and may be set in the range
-20dB to infinity. Because the compression system is based on the Soft
Knee principle, the onset of compression is progressive, so no Ratio
control is necessary.
Attack: Six switchable Attack settings
are provided giving various settings between a Fast to a Slow attack time.
The actual attack time is further modified by the release setting chosen.
Release: There are three fixed Release
times and a further three which are programme dependent. Switch settings 1
through to 3 provide progressively increasing release times, while
positions 4, 5 and 6 cause the release times to vary in a manner which
automatically adapts to the dynamics of the incoming signal.
Output: (Gain) The Output level may be
amplified or attenuated by up to 20dB to compensate for level changes
caused by compression and limiting.
VU Meter: A moving coil VU meter
monitors either the level of the output signal (over the range -10dB to
+10dB with reference to the +4dBu operating level) or the amount of gain
reduction taking place. Because the meter has VU characteristics, it
closely reflects what is actually being heard, though will not respond
quickly enough to register short signal peaks.
VU / GR: Switches the meters to show
either the output level (VU) or the amount of gain reduction (GR).
Norm/Bypass, S/C Listen: In Normal
mode, the signal is passed through the compressor. Bypass only takes the
compressor out of circuit leaving the vacuum tube warmth in the circuit
path; the output signal is taken from the signal insert return point. S/C
Listen routes the side-chain signal directly to the output allowing the
effects of any additional side-chain processing, such as equalisation, to
Stereo Link: Averages the left and
right channel control settings when the unit is used for processing a
stereo signal. The same degree of gain reduction is applied to both audio
channels to prevent image shifting which would otherwise occur whenever
the left and right signal dynamics varied from each other by any
Big Link: Makes the compressor side
chain less sensitive to low bass frequencies, so reducing the ducking
effect caused by bass energy and effectively boosting the bass output.
Mic Input Gain: This switchable
control sets the mic input gain over the range 0 to 66dB in 6dB steps. The
adjacent Clip LED illuminates when excessive Mic gain has been applied and
there is a danger of clipping.
The Auxiliary Input feeds a specialised instrument input stage which
provides both gain and equalisation. The passive Bass and Treble controls
are based on those used in classic tube guitar amplifiers while the Bright
switch puts a peak in the frequency response at around 2kHz to simulate
the voicing of a typical guitar amplifier. A two position high or low gain
switch provides an additional 10dB of gain when required for level
matching or for creating overdrive effects.
Bass EQ: Passive equaliser control,
which can be set to provide up to 15dB of bass boost at 40Hz.
Treble EQ: Passive equaliser control,
which can be set to provide up to 18dB of treble boost at 16kHz.
Gain: Provides up to 30dB of gain at
the Low Gain switch setting or 40dB at the High Gain setting.
Low/High: Sensitivity selector switch.
Adds 10dB of gain in the High position.
Flat/EQ: Switches the equaliser
controls out of circuit when a flat response is required, or for 'A/B'
comparison of EQ effectiveness.
Norm/Bright: Switches in 10dB of boost
at 2kHz in the Bright position, ( when 'EQ' has been selected on the
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The unit should be connected in-line with the signal to be processed or
via suitable insert points. For mono use, each channel may be considered
as being completely independent and set up accordingly. For use with
stereo signals such as complete mixes or submixes, the unit should be
switched to Stereo Link mode. Setting up is simplified by the soft-knee
compressor action which means that it is only necessary to adjust the
Threshold control until the desired degree of gain reduction is achieved.
This is judged partly by ear and partly by observing the gain reduction
meter. In general, a maximum gain reduction of between 10dB and 15dB will
be adequate. If more gain reduction appears necessary, it is worth
considering applying a conservative degree of compression during recording
and then further compression while mixing. The two auto release switch
settings continually optimise the compressor action to suit the dynamics
of the material being processed, setting 5 being optimised for percussive
material and setting 6 for general purpose use. Compressing during a mix
does increase the subjective level of tape and other background noises
during pauses and quiet passages as maximum gain is applied when the
signal level is minimum. For this reason, it is unwise to use more
compression than is strictly necessary. The Gain control may be set to
provide the required output level using the level meter as a guide. Avoid
running at excessively high output levels as this reduces the available
amount of signal headroom and could lead to distortion in extreme cases.
The use of compression on complete mixes can cause a dulling of the sound
but the 1969's tube circuitry combined with the soft-knee action helps
maintain the clarity and transparency of transient sounds.
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QUICK SET UP
Select Stereo Link mode for use with a stereo signal, otherwise
ensure this switch is off.
Select the appropriate signal source for each channel using the selector
Initially, set the Attack selector to the 3 or 4 positions and set Release
to 6 (Programme Dependent).
Set the Mode switch to Normal and the Meter switch to GR.
With the programme material playing, adjust the Threshold control until
the desired amount of gain reduction registers on the meters.
Use the Output Gain control to restore any level lost due to compression.
If necessary, change the Attack and Release settings to suit the material.
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The Aux input has a 2.2M ohm impedance and is suitable for use
with both active and passive guitar pickup systems as well as with
electronic keyboards. Because guitar sounds are so subjective, and because
they vary so much with instrument and playing style, there are no hard and
fast rules to setting up, but a good starting point is to switch Bright
'On' and set the compressor for '3 0r 4' attack and '6' release. The
threshold should be adjusted to give a gain reduction reading of around
5dB on signal peaks. By increasing the Gain control setting, the input
stage can be made to overdrive in a manner similar to that of traditional
valve guitar amplifiers.
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(All measurements taken at +4dBu operating level)
LINE 20K Ohms
MIC 150 Ohms to 600 Ohms
AUX 2.2M Ohms
MAXIMUM INPUT LEVEL +20dBu
OUTPUT IMPEDANCE 50 Ohms
MAXIMUM OUTPUT LEVEL +22dB (balanced)
BANDWIDTH <10Hz to 22KHz -1dB
UNITY GAIN NOISE
MIC (E.I.N.) -134.5dB shorted
-130.5dB @ 150 Ohms
-129.8dB @ 200 Ohms
DISTORTION @ 1KHz
Line Input with BYPASS selected,< 0.1%
Line Input with NORMAL selected,< 0.35%
POWER REQUIREMENTS 100-120Volt or 195-250Volt at 50-60Hz, 38 Watts
FUSE RATING 250mA for 240Volt, 500mA for 120Volt
CONFORMING TO BS EN 60127-2:1991 SHEET III
FUSE TYPE 20mm x 5mm, Class 3 Slo-Blo, 250Volt working
CASE SIZE 482mm (w) x 88mm (h) x 250mm (d)
WEIGHT (incl packaging) 6.0 Kgs
1 100 ms
3 1 sec
4 200 ms to 2 sec semi-automatic/signal dependant
5 500 ms to 5 sec semi-automatic/signal dependant
6 Automatic 1 sec to 10 sec signal dependant